In the printing industry, printing materials are treated after printing in a fusing device, in which toner is fused onto the print material. For this, various processes are known in which energy is supplied to the toner so that it melts and is securely attached to the print material or carrier material. Typically, two heated rollers are used, one placed above, and the other below, the print material. These rollers fuse toner onto the print material by pressure and heat. A release oil, applied to the fusing roller, is used to facilitate removal of the print material from the upper roller or fusing roller. The release oil goes from the fusing roller onto the print material, and has a considerable effect on the gloss on the print material. In printing, gloss is a feature that determines the quality of the printing. Too much gloss is undesirable; with too much release oil on the print material leading to excess gloss in printing. Abrasion or wear of the fusing roller surface is a problem, which affects the transfer of release oil onto the print material and, as a result, unsuitable printings with undesired gloss occur.